FIG 6.

Drug susceptibility profile to menadione and H₂O₂ in L. donovani lines. Promastigote forms of L. donovani lines (WTM and resistant lines A, M, P, S, AS, and SP) were grown as described in Materials and Methods for 72 h at 28°C in the presence of increasing concentrations of menadione (A) or H₂O₂ (B). Cell viability was determined using an MTT-based assay. The data are the mean EC₅₀ ± SD from three independent experiments. Significant differences versus the WTM were determined using Student's t test (*, P < 0.01; **, P < 0.005; ***, P < 0.001). The black line indicates the threshold at which the levels of EC₅₀ have been modified versus WTM.